Air-brake apparatus.



No. 763,834. PATENTED JUNE 28, 1904. 0. A. ALBXANDER..

AIR BRAKE APPARATUS.

APPLICATION rum) arm. 10. 1903. N0 MODEL.

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' larger scale, showing the piston-valve.

Patented June 28, 1904.

PATENT ()EEIc OLIVER A. ALEXANDER, OF PHILADELPHIA, PENNSYLVANIA.

AIR-BRAKE APPARATUS.

SPECIFICATION formingpart of Letters Patent No. 763,834, dated June 28, 1904.

T rtZZ whom it may concern.-

Be it known that I, OLIVER A. ALEXANDER, a citizen of the United States,residing at Philadelphia, in the county of Philadelphia and State of Pennsylvania, have invented a certain new and useful Improvement in Air-Brake Apparatus, of which the following is a full, clear, and exact description.

The object of this invention is to provide a valve to be used in place of the ordinary engincors valve in an air-brake system by means of which the train-pipes may be filled and maintained full without excess of pressure and the necessary reductions of pressure for service and emergency braking be quickly and effectively accomplished.

The invention consists of a piston-valve communicating directly with the main reservoir or air-pump and having an indirect communication with the train-pipes through a governor or automatic valve for filling such pipesand capable of direct communication with the train-pipes for service and emergency braking or stops, all as I will proceed now more particularly to set forth and claim.

In the accompanying drawings, illustrating the invention, in the several figures of which like parts are similarly designated, Figure 1 is a side elevation of one form of the invention. Fig. 2 isa front end elevation thereof. Fig. 3 is a longitudinal vertical section, on a Fig. 4 is a vertical section of the governor or automatic valve detached.

The cylinder 1 may be made with an integral or a detachable head 2 at one end and with adetachable head 3 at the other end, provided with any suitable gland 4. A nipple 5 is provided for connection with the source of pressure, such as a main reservoir or an airpnmp, and another nipple 6 is provided for connection with a service-conduit, such as a train-pipe. The cylinder is provided with a lining 7, having the ports 8, 9, 10, 11, 12, and 13 and the vents 14, 15, and 16. A chokeplug 17 is provided in the port 13. The piston or valve proper is shown as made of two connected heads 18 and 19, respectively, pro vided with laps 20 and 21. The lap 20 is provided with the ports 22 and23 upon oppo- Application filed September 10, 1903. Serial No. 172,667. (No model.)

site sides of the head 18, and the lap 21 is provided With the ports-24 and 25 on opposite sides of the head 19. The piston has a rod 26 connected therewith by the lostmotion connection 27, and this piston-rod is connected with a lever 28, pivoted at 29 to the segmentbracket 30, mounted upon the cylinder,'said bracket having an arc rack 31, with which the lever is engaged to hold the piston in any desired position, as will be presently explained.

The port 11 opens into a channel 32, made in a boss 33, from which the nipple 6 depends, and this channel opens into a channel 34, made in the valve-chest 35, which is provided with a flange 36, by means of which it may be bolted to the boss 33. This valve-chest has a port 37, which opens into the nipple 6, and has another port 38, also opening into the nipple 6, A-two-headed valve 39 has one of its heads interposed between these ports 37 and 38 and is provided with a lap 40 to open and close the port 37. This valve is supported upon a tension-spring 41, arranged within the valve-chest and capable of adjustment therein for varying its tension by means of a nut 42 or other suitable device.

I have thus described my construction as for use in connection with the ordinary railway air-brake system; but without thereby limiting my invention to this one application thereof I will proceed further to describe its operation in such connection: The air-pressure enters the piston-valve through nipple 5 and passing thence between the heads of the piston-valve goes through ports 23 and 11 into the channel 32, through the port 34 into the valve-chest 35 and between the heads of its valve, and escapes thence through the port 37 into the nipple 6, and so on into the train-pipe to the auxiliary reservoirs and brake-cylinders, and, as shown, this is the position of parts in running. It will be observed that the pressure entering through port 37 into the nipple and train-pipe also flows back through the port 38 above the valve 39, and as soon as the pressure above the valve 39 becomes greater than the tension of the spring said spring is compressed and the valvev is moved downwardly and its lap 40 closes the port 37, and thus the trainpipe pressure is maintained. If by leakage or otherwise the train-pipe pressure is diminished, the valve 39 under the tension of its spring il will again open the port 37 until the maximum pressure is restored. When it is desired to apply the brakes, as for a service-stop, the lever 28 is moved to the right, so as to force the pistonvalve to the left until the port 22 is in communication with the port 9, thus allowing the air in the train-pipe to escape into the righthand end of the cylinder and out into the atmosphere through the vent 14, which may be a choked port, such as shown at 17. The lever may then be moved back to the leftinto what may be called the lap position without changing the position of the piston by reason of the loose connection 27. Upon the firstmentioned motion the ports 24 and 25 in the lap 21 were brought into register with the ports 12 and 13, whereby air was admitted into the left-hand end of the cylinder to exert its pressure against the left-hand end of the head 19 and by the same movement the lap 21 covering vent 15. This admission-pressure may be accomplished more or less slowly by adjustment of the choke-plug 17; but as it flows into the left-hand end of the cylinder it gradually overcomes the pressure of the escaping air in the right-hand end of the cylinder, and thus returns the main piston to a lap or running position, according to the position of the operating-lever, thus effecting what may be termed an equalization movement. For

an emergency application the lever is pulled over to the extreme right-hand end of the segment, whereby the valve is moved so as to place the port 22 in communication with the other port 10, opening into the nipple 6, so that the lap 20 will wholly uncover the exhaust 8 to the atmosphere, thus allowing the pressure to escape rapidly. The full release is effected by pulling the lever over to the extreme left-hand position on the segment, thus bringing the port 23 into register with port 10 and exposing the leakage-port 16 to the atmosphere, and so permitting the air to escape, and thus warning the engineer. Of course the main piston-valve should be carried in running position and not in full release.

The vent 15 is provided to relieve that end of the cylinder of any undesirable pressure, and a pop-valve 43 may be placed in the front head of the cylinder and set at a low pressure (three or four pounds) to overcome any compression that would ensue when the piston moves in that direction.

I have thus shown and described one embodiment of my invention sufiicient to carry it into efiect; but I do not wish to be understood as limiting the invention to such single form thereof and am aware that it is susceptible of variation in construction and arrangement.

What I claim is 1. A double-headed piston-valve, communicating with the source of pressure between its heads, a service connection, and an automatic governor-valve interposed between the piston-valve and its service connection and responsive to variations in pressure in said service connection.

2. A double-headed piston-valve, communicating with the source of pressure between its heads, a valve-cylinder having outlets on opposite sides of the two heads, a service connection, and an automatic governor-valve interposed between the piston-valve and its service connection and responsive to variations in pressure in the service connection.

3. A piston-valve, communicating directly with the source of pressure, aservice connection, and an automatic governor-valve interposed between the piston-valve and its service connection, said piston-valve ported to communicate directly with the service connection and the atmosphere and simultaneously closing communication through the governorvalve.

A. A piston-valve, communicating directly with the source of pressure, a service connection, and an automatic governor-valve interposed between the piston-valve and its service connection, and comprising a valve-chest ported to communicate with the piston-valve and having a valve communicating on opposite sides with the service connection and set to resist a predetermined pressure.

5. A piston-valve, communicating directly with the pressure-supply, a service connection, two ports of diiferent area connecting the service connection with the valve, independent atmospheric ports for said serviceconnection ports, and means to control the said several ports independently.

In testimony whereof I have hereunto set my hand this 4th day of September, A. D. 1903.

OLIVER A. ALEXANDER.

Witnesses:

F. B. \NHEELER, T. MAURICE VVIDBY. 

